Studies of the membrane proteins and glycoproteins of red cells and platelets will be carried out utilizing a nonpenetrating radioactive membrane label (125I) diazodiiodosulfanilic acid, membrane isolation, protein quantification, and sodium dodecyl sulfate polyacrylamide gel electrophoresis with staining for proteins and glycoproteins. Normal cells, incubated cells, stored cells, cells subjected to various perturbations, and cells from patients with certain diseases will be studied. BIBLIOGRAPHIC REFERENCES: George JN: Platelet membrane glycoproteins--alteration during storage of human platelet concentrates. Thromb. Res. 8:719-724, l976. Sears DA and Conklin GT: Membrane binding of intracellular protein and ATP production in incubated hereditary spherocytosis (HS) red cells. Blood 46:1006, 1975.